"Most of you will die... but that is a sacrifice I am willing to make!"

Explanation: During the Second Punic War, the Roman Republic suffered massive casualties against the Carthaginian (’Punic’) military genius Hannibal. I mean massive. Not literally half, but often estimated at a full 20% of the military-age male citizens of Rome. And Rome kept sending out armies to fight. They didn’t hear no bell.

For comparison, WW1 collapsed at about ~15% of the military age male citizens dead in most of the relevant defeated countries.

Adding to the sincerity of the desperation, rich men, including of the highest and most powerful classes of Rome, who had evaded the draft during this time of crisis had their property and citizenship stripped from them and were sometimes enslaved in addition. Everybody fights for the survival of the Res Publica!

For this reason of near-mental-illness level tenacity, the Romans did actually eventually win the Second Punic War, reducing Carthage from a sprawling hegemonic empire (like the Roman Republic itself) to an indebted city-state forbidden to raise military forces of its own.